THE VOLCANO THAT SHOOK THE EARTH

The eruption of the Hunga Tonga-Hunga Ha'apai volcano was a once-in-a-century geological event - and now the clock is ticking to study its effects...

- FREDERIK RUYS

The eruption of the submarine Hunga Tonga-Hunga Ha’apai volcano on 15 January 2022 left thousands of people without homes, supplies and internet. At the time of writing, there were three confirmed deaths related to the eruption, two of which were locals, and one British national.

The volcano’s explosion sent shock waves as far as Alaska and the UK and caused a tsunami that affected the shores of Australia, the US and Russia. Around 10 hours after the eruption, people in Miami in the US – more than 11,000km away from the volcano – saw pressure ‘waves’ at speeds of 1,100km/h. These acoustic ripples in the air were essentially travelling at the speed of sound through the atmosphere.

Five days after the eruption, the volcano’s activity appeared to have stopped at surface level, although volcanologists could not say what was happening under the water.

Scientists still don’t know why the Hunga Tonga-Hunga Ha’apai volcano erupted, but as it is a submarine volcano, it’s likely to have been a sudden reaction, not something that had been bubbling under the surface for some time, said Dr. Samuel Mitchell, a specialist in volcanic submarine systems at the University of Bristol.

• The aftermath

There are two uninhabited islands on the edge of the volcanic crater: Hunga Tonga and Hunga Ha’apai. Following the eruption, satellite images indicate these islands are a lot smaller, meaning the explosion likely destroyed a large part of the land. Scientists can’t be sure whether the collapse of the crater caused the huge movement of water that created the tsunami, or if an explosion below the surface, propelling water away from the volcano, could have been the source.